‘Radical Nature’ is the name of the BarbicanArtGallery’s summer exhibition, and also, coincidentally, the name of a book whose central argument is that all living things have a consciousness. One can only assume then, that the point of gathering together such an eclectic range of environmentally conscious artists, from across five decades, is to suggest that man needs to have a more respectful attitude towards the natural world. This is actually a very strange exhibition for an art gallery, in that many of the works are either living or growing, or at least not long dead. It is a fantastical and interesting display, but unfortunately – somewhere in the sheer scope of the spectacle – the message, if indeed there is one, gets lost.

Curator Francesco Manacorda says the idea for the collective show has been germinating for some years, but it is now both timely and possible. It stems from his own personal interest in the parallel between the cultural responses to the societal crises of the 1970s and today. The land artists, environmentalists and hippies inspired by the oil embargoes of the 1970s and seminal texts like Rachel Carson’s DDT exposé, ‘Silent Spring’, are the ancestors of a current surge of artists exploring similar issues – R&Sie’s biomimetic house that is reclaimed by plants, Lara Almarcegui’s charting of wild Hackney shortly to be consumed by the 2012 Olympics.

But unfortunately the undoubtedly impressive land art forms of pioneers like Robert Smithson and Agnes Denes lose something in translation – they are reproduced in the gallery through photographs and grainy films at best. In one room the remains of a piece by Joseph Beuys (whose lifelong obsession with felt and fat is borderline pathological) are actually laid out, but look more like a strange scrap yard, with a lot of disconcertingly stained tubing that had once been used to pump honey as part of the original installation – although this is hardly a meaningful explanation.

Some of the other installations are undeniably aesthetically pleasing and have a clearer message – a greenhouse full of mass-produced orchids, an upturned tropical forest and a tiny formal garden in a mirrored box being the obvious examples. If you touch anything though, or heaven forbid, walk on the grass, you’ll be swiftly reprimanded. The Centre for Land Use Interpretation is represented through a mesmerising slideshow and a kiosk explaining their work. And the timber pavilion on the Lakeside Terrace is genuinely delightful, framing views of the Barbican’s concrete towers and water-lilied pond, with the sound of the fountains drowning out the city.

So there is plenty that is of interest and value here (although there is also some downright silly stuff – images of 70s collective Ant Farm explaining, with drawings, the ‘dolphin embassy’ concept to a dolphin;a video of Joseph Beuys insisting that peeling a potato counts as art), but little discernible narrative. What, really, does Buckminster Fuller have to do with a mugshot of a fox stealing a booby-trapped frankfurter? And the layout doesn’t help in this – there is no chronology, and few obvious thematic links. Each piece is an island, some literally so. Although broadly linked by the themes of ‘Land Art, Environmental Activism, Experimental Architecture and Utopianism’, broad is the operative word; the spectrum of artists and agendas is too wide. Without telling a story it’s difficult to argue a case – what is the message? And anyway few of them offer any kind of practical solution for a healthier relationship between man and nature. But then of course it’s art – it shouldn’t have to, should it?

The lasting impression is of nature potted, preserved, carved up, pressed and sculpted, twisted into a variety of art forms. The making of the exhibition itself, it seems, is under suspicion for the very crimes against nature it accuses the rest of the world of perpetrating, in spite of the recycled paper used for the (actually wonderfully informative) descriptions accompanying each piece. In aesthetic terms they have succeeded in creating a highly unusual landscape inside the gallery, but if you’re looking for any more meaningful contribution to the climate change debate you’re likely to leave disappointed.